The operation of hydrogen production facilities in locations experiencing cold winters presents special challenges. During winter, these facilities can experience sustained ambient temperatures well below 0° C. and as low as −34° C., depending on location. In winter, one obvious problem is freezing of makeup water used for the steam system and utility water supplying cooling medium. During winter months, it may not be possible to use a water cooling tower. Another problem is the formation of solid hydrates and sulfur deposition in hydrocarbon streams.
To solve the problem of steam system makeup water freezing, hot makeup water may be provided to the hydrogen production facility. The use of hot makeup water then requires a change in the heat transfer network as compared to systems not receiving hot makeup water. Cold makeup water is conventionally used to cool the reformate and condense water from the reformate. Without cooling provided by cold makeup water, other means for cooling the reformate must be found.
Closed loop cooling water utility systems may not be provided in locations experiencing sustained cold winters due to cooling tower freezing problems during winter operation. Without the closed loop cooling water utility systems, forced draft air coolers are used to reject low level heat to the atmosphere. Due to the lack of other available coolants, the heat duty of the air coolers needs to be increased. These air coolers must be sized for the higher temperatures expected during the summer, where a lower temperature driving force is available, resulting in larger, more costly equipment.
It is apparent that designs optimized for temperate conditions where there is little chance of freezing may not be well-suited for cold climates and/or that the energy efficiency may be significantly deteriorated and/or the size/cost of required heat transfer equipment may be significantly increased.
Industry desires a cost-effective hydrogen production process that operates energy efficiently in both conditions of warm summers and cold winters.
Industry desires a hydrogen production process that avoids freezing of any process water streams.
Industry desires a hydrogen product process that avoids solid deposits in hydrocarbon streams due to hydrate formation and/or sulfur deposition.
Industry desires reduce the required size of forced draft air coolers to cool the reformate when cold makeup water is in short supply.
Related disclosures include U.S. Pat. No. 7,377,951B1 and U.S. 2011/0277962A1.